METALLOGENY OF THE BEATON CAMBORNE MINING CAMP LARDEAU DISTRICT (082K 12 & 13) By B.N. Church and L.D. Jones, B.C. Geological Survey KEYWORDS: Beaton, Camborne, Trout Lake, wagon road was built to Trout Lake from veins, gold silver, lead, zinc, molybdenum, tung- Thompsons Landing (renamed Beaton in sten, Lardeau Group, Kootenay Arc. 1903) on the Northeast Arm of Upper Arrow Lake. In the succeeding eight years many gold claims were staked and developed. Four or five INTRODUCTION stamp mills were erected to process the quartz- The Beaton area (NTS 082K12,13) compris- rich vein ore and the town of Camborne, found- es several former mines and dozens of mining ed in 1901, grew rapidly. In 1902 the railway prospects scattered across 200 square kilometres was extended to Gerrard at the south end of in the Lardeau district, West Kootenay region of Trout Lake and steamer service began on the southeastern British Columbia. The area is cen- Arrow Lakes. Activity peaked in 1904 but the tred just north of the settlement of Trout Lake, operations at Camborne soon proved unprof- 60 kilometres southeast of Revelstoke and 140 itable due to a combination of poor manage- kilometres north of Nelson in the heart of ment, low ore grades and metallurgical prob- Selkirk Mountains lems. By far the greatest proportion of the ore Prospecting for metalliferous deposits in the that was shipped was hand sorted to produce a Lardeau district began prior to 1890. A crew led silver-lead product. Large quantities of ore con- by Peter Walker, following up on a rumor of new taining sphalerite, accompanied by appreciable mineral discoveries, travelled down the amounts of silver and gold, were left on mine Columbia River from Revelstoke to Upper dumps because of a penalty imposed for zinc by Arrow Lake and overland to Trout Lake. Mining the smelters. By 1908 there was a decline in activity started in the late 1890s after more activity and by 1920 Camborne was practically a prospectors overflowed from the Slocan and ghost town. In 1927 the area revived somewhat Kootenay Lakes area. By 1899 mineral claims when the Multiplex Mining, Milling and Power were located near Beaton on the Northeast Arm Co. renewed work on their properties along Pool of Upper Arrow Lake and along the Creek. During the years 1935 to 1941 activity Incomappleux (Fish) River. consisted mainly of mill cleanup and salvage The history of the Lardeau district revolves projects. Then there was a resurgence of explo- about three mining camps - the Camborne camp ration and development in the 1950s. The on the Incomappleux River east of Beaton, the Spider mine was brought into production in Ferguson camp east of Trout Lake and the Poplar 1952 and continued operations until 1958. Creek camp south of Trout Lake. This paper dis- During this period deposits other than just cusses the mines and mineral occurrences in the silver and lead were explored in the district. For Beaton map area including the Camborne camp. example in 1942 the Lucky Boy mine on Trout In the early years gold and silver-lead ores Mountain produced 20 tonnes of scheelite (cal- from the the Camborne camp attracted the most cium tungstate) in addition to the previous pro- attention. Claims on Sable Creek, Lexington duction of important amounts of silver and lead. Mountain and at the head of Mohawk Creek, Although molybdenite was first reported on the were responsible for much of the interest. In July property in 1917, it was not until 1969 and 1975- 1899, good gold values were obtained from a 1982 that further exploration led to the delin- quartz vein on the Eva claim on Lexington eation of major molybdenite reserves at what is Mountain and a prospecting rush ensued. A now known as the Trout Lake deposit. Geological Fieldwork 1998, Paper 1999-1 193 overlain by phyllitic schists, quartzites and lenticular greenstone formations. The Milford and Kaslo groups are metamorphosed oceanic assemblages that include phyllites, thinly bed- ded calc-silicate metasedimentary rocks, chert beds, basic volcanic rocks and serpentinites (Fyles, 1967). The Mesozoic formations constitute the Quesnel terrane that lies along the western side and within the curvature of the Kootenay Arc. The Kaslo and Rossland volcanics (Hoy and Revelstoke Dunne, 1997) and the Slocan argillite, slate and limestones are important units in this terrane and contain significant silver-lead-zinc deposits typ- Vancouver ical of the Lardeau and Slocan mining districts. Beaton Area Many batholiths and arrays of small stocks Figure 1. Location map, Beaton-Camborne mining interrupt the continuity of the older deformed camp. stratigraphic succession throughout the Intermittent exploration activity continues in Kootenay Arc. The Kuskanax and Nelson the area driven by changing market conditions batholiths are the largest intrusions. They are for precious and base metals, new geophysical predominantly granite and granodiorite in com- and geochemical methods and new geological position although diorite, monzonite and syenite interpretations. are locally important phases. The age of these rocks is generally considered to be middle or late GEOLOGICAL SETTING Jurassic age (Armstrong, 1988; Sevigny and Parrish, 1993). The geology of the Beaton area (NTS The Nelson batholith and many of the relat- 082K/12,13) comprises diverse lithological ele- ed granitic stocks have local zones of intense ments belonging to several tectonic terranes deformation around their margins. Regional (Figure 2). On a regional scale, the Beaton- structures are deflected into near parallelism Camborne mining camp is within the Kootenay along the margins of these intrusions. It may be Arc which lies between the Windermere-Purcell that antecedent structures controlled the anticlinorium on the east and the Monashee and emplacement of the granitic masses. Shuswap metamorphic complexes to the west Cretaceous and Tertiary intrusions are com- and northwest (Reesor and Moore, 1971; mon in the northern part of the arc and to the Reesor, 1973). east. These include medium-size plutons and The Kootenay Arc is a 400-kilometre-long small stocks of fresh granite, monzonite and curving belt of early Paleozoic to Mesozoic sed- syenite such as the Battle Range, Fry Creek plu- imentary, volcanic and metamorphic rocks. It tons and the Mount Toby and Glacier Creek trends northeast across Washington state into stocks east of Kootenay Lake (Smith and British Columbia, then north along Kootenay Gehrels, 1992). Lake and northwest into the Arrow Lake and Revelstoke area. Lardeau Group Along Kootenay Lake the arc succession comprises the Hamill, Badshot, Lardeau, The Lardeau Group, as defined by Fyles Milford, Kaslo, Slocan and Rossland groups. and Eastwood (1962) in the Ferguson area, The Hamill, Badshot and Lardeau constitute the consists of 6 conformable Lower Paleozoic early Paleozoic pericratonic Kootenay terrane; units named the Index, Triune, Ajax, Sharon the Milford and Kaslo belong to the accreted late Creek, Jowett and Broadview formations. This Paleozoic (and early Mesozoic) Slide Mountain succession was believed to be an upright terrane. The Hamill is mostly quartzite; the stratigraphic sequence having the Index Lardeau comprises a lower calcareous section Formation at the base and the Broadview 194 British Columbia Geological Survey Branch 51O 00' 118 00' 1 117 45' 1 7 O O O 3 0 ' 50O 45' N 048 kilometres 50O 30' Figure 2. Geology of the Beaton area (modified after Read, 1976, and Read and Brown, 1981). See legend next page. Geological Fieldwork 1998, Paper 1999-1 195 Figure 2. Legend Formation at the top. However, the highly formation is highly variable, black and grey folded condition of the beds, the lack of facing phyllite facies predominate near the base at the indicators and the presence of faulted contacts contact with the Badshot Formation, while hindered verification of this interpretation green phyllite predominates in the upper part (Smith and Gehrels, 1992). of the unit (Fyles and Eastwood, 1962). The The Index Formation is the most extensive Index Formation is overlain by a conformable unit in the Lardeau Group. The Index assemblage of black siliceous argillite, grey Formation comprises a thick sequence of grey, quartzite and black siliceous argillite known green and black phyllite, limestone and thick respectively as the Triune, Ajax and Sharon calcareous phyllite, tuff, tuffaceous Creek formations. The Jowett Formation is a greywacke, pillow basalt and rare quartzite and greenstone unit intercalated with the quartzo-feldspathic gritty sandstone. In vicini- Broadview Formation. The Jowett consists of ty of McDougal Creek, along the volcanic breccias and pillow lavas (Photo 1) Incomappleux River, the formation consists of altered locally to chlorite schist. The predomi- crystalline limestones and interbanded slates nant lithology of the Broadview Formation is and phyllites (Figure 2). Many of the limestone grey green, gritty quartz wacke or subarkosic bands are highly carbonaceous - some of them wacke with grey to black or green slate or containing a considerable amount of graphite, phyllite interbeds. Two important bands of while other bands contain sufficient chlorite to quartzite, assigned to the Broadview give a green colour to the rock. Although the Formation, cross the valley of the 196 British Columbia Geological Survey Branch have established a somewhat older age range for these rocks (Smith and Gehrels, 1992). The Nelson batholith underlies much of the western part of the Kootenay district where it is a complex of intrusives rocks differing in struc- ture, texture and composition. The Nelson batholith is the principal rock type within the Slocan City camp and in this area it is subdivid- ed into three phases (Cairnes, 1934) - granitic porphyry, crushed porphyry, and massive equigranular granite and granodiorite. The granitic porphyry is the predominant phase and hosts most of the ore deposits. Exposed surfaces of the rock are light grey with a flesh-colour hue due to weathering of the feldspar.